[en] A new spectrofluorimetric method was developed for the determination of lysozyme. Under the optimum conditions, Eu³⁺-metacycline formed a ternary complex in close proximity with lysozyme and then intramolecular energy transfer occurred from metacycline-lysozyme complex to Eu³⁺, which resulted in the enhancement of the characteristic peak of Eu³⁺ at 612 nm. The enhanced fluorescence intensity is in proportion to the concentration of lysozyme, and the linear range was 0-3.5x10^-5 mol l^-1 with limit of detection of 4.74x10^-7 mol l^-1, respectively. The developed method was practical, simple, sensitive and relatively free from interference of coexisting substances and had been successfully applied to the determination of lysozyme in serum and urine samples. The mechanism of fluorescence enhancement between the Eu³⁺-metacycline complex and lysozyme was also studied

[en] Graphical abstract: In order to achieve improved near infrared downshifting, we have investigated the effect of Pr³⁺ doping on the energy transfer efficiency from Ce³⁺ to Yb³⁺ in the YAG host. - Highlights: • Synthesis and characterization of tri-doped Y₃Al₅O₁₂ (YAG). • Efficient energy transfer in YAG:Ce³⁺, Pr³⁺, Yb³⁺. • Discussion of mechanism of energy transfer in tri-doped host. • Potential application in c-Si solar cell. - Abstract: Novel YAG:Ce³⁺, Pr³⁺, Yb³⁺ phosphors were synthesized using a high temperature solid state reaction method. The XRD patterns revealed that the obtained samples belong to the single phase YAG. The optical spectra demonstrated that Pr³⁺ could be a bridge to facilitate the energy transfer from Ce³⁺ to Yb³⁺ in the YAG host. Blue light excited Ce³⁺ and a yellow emission from Ce³⁺ together with a near infrared emission of Yb³⁺ was obtained. The effect of Pr³⁺ doping on the energy transfer efficiency was explored. When the doping concentration of Pr³⁺ increased, the yellow emission intensities of Ce³⁺ decreased and the near infrared emission intensity of Yb³⁺ increased monotonously. Hence, the efficiency of energy transfer from Ce³⁺ to Yb³⁺ is enhanced by the addition of Pr³⁺, implying that the YAG:Ce³⁺, Pr³⁺, Yb³⁺ phosphors are promising downshifting materials and have the potential to be used in Si-based solar cells.

[en] Influences from different fields of mesons and photons on the relativistic symmetry are reinvestigated with the similarity renormalization group method (SRG). The energy splittings of pseudospin doublet and spin doublet are extracted from the SRG calculations. From the point view of the SRG method, ω field is revealed to exert great effect on the pseudsospin symmetry by nonrelativistic term, dynamical effect and spin-orbit interaction. Both nonrelativistic term and dynamical effect are also dominant in the influence of the σ field on the pseudsospin symmetry. With the increasing strength of the photon field, the evolution of nonrelativistic component provides the main contribution to the increase of the total pseudospin energy splitting. The nonrelativistic term play the major role in influencing the isospin asymmetry in the pseudospin symmetry. As for the ρ meson field, all three terms exert contrary influences on the pseudospin splitting between neutron doublet and proton doublet. The spin symmetry which is quasi-isospin symmetric is revealed to be due to the relativistic effect by spin-orbit term.

[en] The log–polar transform (LPT) is introduced into the star identification because of its rotation invariance. An improved autonomous star identification algorithm is proposed in this paper to avoid the circular shift of the feature vector and to reduce the time consumed in the star identification algorithm using LPT. In the proposed algorithm, the star pattern of the same navigation star remains unchanged when the stellar image is rotated, which makes it able to reduce the star identification time. The logarithmic values of the plane distances between the navigation and its neighbor stars are adopted to structure the feature vector of the navigation star, which enhances the robustness of star identification. In addition, some efforts are made to make it able to find the identification result with fewer comparisons, instead of searching the whole feature database. The simulation results demonstrate that the proposed algorithm can effectively accelerate the star identification. Moreover, the recognition rate and robustness by the proposed algorithm are better than those by the LPT algorithm and the modified grid algorithm. (paper)

[en] In this study, we aimed to determine the dosimetric differences between 3D-printing multi-channel applicator interstitial brachytherapy (3DP-ISBT) and conventional three-dimensional intracavity treatment (ICBT) for cervical cancer with a high-risk clinical target volume (HR-CTV) of 50 ∼ 90 cm³, to determine the feasibility of using 3DP-ISBT, and to provide a basis for the application of 3DP-ISBT in clinical practice. The study included 27 patients with cervical cancer and an HR-CTV of 50 ∼ 90 cm³ who underwent radiotherapy at Gansu Provincial Cancer Hospital between May 2017 and May 2019. Among them, 14 patients were treated with 3DP-ISBT and 13 were treated with ICBT. With a prescription dose was 6 Gy, evaluated the volume of the HR-CTV, the dosimetric differences in D₉₀ (received absorbed dose of 90% of the HR-CTV) of the HR-CTV, bladder, and rectum. Compared with the ICBT group, the 3DP-ISBT group showed no statistical differences in volume of the HR-CTV, D₉₀ of the HR-CTV, and D_1cc, D_2cc, and D_3cc of the rectum (doses received by 1 cm³, 2 cm³, and 3 cm³ of the rectal volume) (p > 0.05). D_1cc, D_2cc, and D_3cc of the bladder were lower in the 3DP-ISBT group than in the ICBT group, and the difference was statistically significant (p < 0.05). 3DP-ISBT for cervical cancer with an HR-CTV volume of 50 ∼ 90 cm³ can meet clinical requirements. The target can be irradiated with a sufficient dose in large-volume cancer and can protect the bladder better than can ICBT, however, there are no advantages in terms of protection of the rectum. (authors)

[en] Calcined layered double hydroxide (CLDH) as a potential adsorbent to remove iodide contaminants was investigated in batch mode. The uptake capacity of calcined LDH is higher than that of LDHs as precursor, due to their different mechanism which is supported by XRD and TG-MS measurements. The influences of CLDH structure, dosage of CLDH, initial concentration of iodide ion and co-existing anions on the removal of iodide ion have been investigated. The applicability of the Langmuir isotherm shows that the maximum uptake capacity was approximately 376 mg/g, and Gibbs free energy (ΔG⁰) for the process is -23.8 kJ/mol. The negative ΔG⁰ value shows the spontaneity of the adsorption process. (author)

[en] We propose a refractive index sensor applied in liquid detection based on magneto-optical surface plasmon resonance. The device is made of a prism-coupling system, which consists of a prism and a CeYIG/Au/liquid waveguide. Systematic simulations using the finite element method and 4  ×  4 transfer matrix methods are implemented to calculate the figure of merit (FOM) of sensitivity. Calculation results show that a FOM of 5.022/RIU for refractive index variation from 1.330 to 1.345 can be obtained when the incident wavelength is 980 nm. The proposed structure can achieve high angular sensitivity for the magnetic field of the proposed structure concentrated in the sensing medium. Meanwhile, our sensor, with gold as the bottom layer, is a better hydrophily for the molecular self-assembly technique compared with other conventional sensors, which makes it more practical in applications. (paper)

[en] We propose a new structure to enhance the transverse magneto-optical Kerr effect (TMOKE) via resonant photon tunneling. In trilayer structures with a magnetic dielectric layer sandwiched between non-magnetic metal layers, an enhanced TMOKE can be observed. The TMOKE in Au/Ce:YIG/Au trilayers with different widths of magnetic dielectric layers are calculated using a 4  ×  4 transfer-matrix method, in which the maximum absolute value reaches 0.7. Based on the enhanced TMOKE, we apply the structure proposed above in magnetic field sensing, and TMOKE values are calculated when the external magnetic field intensity is increasing. Compared with other magnetic field sensing methods, the Au/Ce:YIG/Au trilayer possesses a very simple structure and shows high sensitivity to magnetic field variation, which is promising as a highly integrated and sensitive magneto-optical device. (paper)

[en] Highlights: • Very high W concentrations are observed in some geothermal waters from YST. • Vastly different W/Mo ratios of the YST waters are ascribed to their various geneses. • Fe-bearing minerals in hot spring sediments are the major sink for geothermal W. • Low pH is favorable for the adsorption of geothermal W onto Fe-bearing minerals. • Immobilization of geothermal W was little affected by its polymerization/thiolation. -- Abstract: Tungsten is of extraordinarily high concentrations in the geothermal waters discharging from several representative Tibetan magmatic hydrothermal systems (up to 1103 μg/L), which are also characterized by exceptionally high W/Mo molar ratios (up to 1182). The geochemical origins of the tungsten in these geothermal waters were investigated, with a comparison to those from Rehai, the sole magmatic hydrothermal system in Yunnan, which is another major part of the Yunnan-Sichuan-Tibet Geothermal Province of China. The results show that the lithology of reservoir host rocks is the primary factor controlling the tungsten concentrations of the geothermal waters, although the contribution of magmatic fluid input cannot be ruled out. In this study, the geothermal waters are generally rich in sulfide, and therefore the molybdenum in the reservoir fluids has been substantially precipitated as the form of molybdenite; in contrast, the reservoir fluids are well undersaturated with respect to tungstenite which is much more soluble than molybdenite. Thus the neutral/alkaline hot springs, i.e. the evolved reservoir fluids, have high W/Mo molar ratios as well. In the hot spring sediments, the distribution pattern of tungsten is quite different. The concentrations of tungsten are the highest in the sediments with high iron concentrations collected from the acid hot spring vents and outflow channels. The adsorption of aqueous tungsten onto iron-bearing minerals, like goethite or pyrite, is favorable at acid pH values and thereby responsible for the very high tungsten concentrations of these acid hot spring sediments. The proportions of thiotungstates in total tungsten are quite low for all the hot springs, as indicated by thermodynamic calculations, suggesting that thiolation of tungstate has little impacts on the environmental transport and fate of geothermal tungsten in the investigated hydrothermal areas. This is the first study to report the tungsten geochemistry of hot springs in mainland China.

[en] Particles can be removed from a silicon surface by means of irradiation and a laser plasma shock wave. The particles and silicon are heated by the irradiation and they will expand differently due to their different expansion coefficients, making the particles easier to be removed. Laser plasma can ionize and even vaporize particles more significantly than an incident laser and, therefore, it can remove the particles more efficiently. The laser plasma shock wave plays a dominant role in removing particles, which is attributed to its strong burst force. The pressure of the laser plasma shock wave is determined by the laser pulse energy and the gap between the focus of laser and substrate surface. In order to obtain the working conditions for particle removal, the removal mechanism, as well as the temporal and spatial characteristics of velocity, propagation distance and pressure of shock wave have been researched. On the basis of our results, the conditions for nano-particle removal are achieved. (paper)